Research Center for Geomechanics and Mining Practice Problems, Saint-Petersburg Mining University, Saint-Petersburg, Russia:

K. V. Morozov, Head of Laboratory, Candidate of Engineering Sciences, morozov_kv@pers.spmi.ru
D. N. Demekhin, Senior Researcher
S. N. Kotlov, Senior Researcher, Candidate of Geologo-mineralogical Sciences

Eurochem VolgaKaliy, Kotelnikovo, Russia:
V. I. Abashin, Deputy Chief Geologist

Potash mining is usually implemented under water bodies both on ground surface and underground. Potentiality of hydraulic connection to form between these bodies and mine roadways because of natural (jointing) or induced (aquifer undermining) reasons can cause flooding of some roadways or total closure of mines. An obligatory flooding protection structure in potash mine construction and mining is a waterproof wall. Such walls are constructed in case of hazards of water inrushes in mines. Designs of the water retaining walls take into account the engineering, geomechanical and hydrogeological factors, including the critical factor of permeability. Aimed at evaluation of permeability, the Saint-Petersburg Mining University developed an appropriate procedure and accomplished in-situ experimental activities in roadways on some mine of EuroChem Group AG, at a depth of 1000 m below ground surface. The geological structure and great depth of occurrence of the test roadways govern a high hydrostatic pressure. The in-situ test data processing shows that the permeability of rocks composing a safety pillar is 2 orders of magnitude lower than the preset threshold. The results imply feasibility of construction of water-retaining walls within the limits of the safety pillar. The authorial procedure can be used by research and production agencies when selecting correct construction sites and parameters of waterproof walls aimed at mine flooding protection.

1. Zubov V. P., Kovalski E. R., Antonov S. V., Pachgin V. V. Improving the safety of mines in developing Verkhnekamsk potassium and magnesium salts. GIAB. 2019. No. 5. pp. 22–33.
2. Litvinenko V. Advancement of geomechanics and geodynamics at the mineral ore mining and underground space development. Geomechanics and Geodynamics of Rock Masses : Proceedings of the 2018 European Rock Mechanics Symposium. London : Taylor & Francis Group, 2018. Vol. 1. pp. 3–16.
3. Boltyrov V. B., Vatagina V. E. Dangerous induced and natural processes on Verkhnekamsk potassium–magnesium salts (Perm Region). Emergency Protection of People and Areas : II International Conference Proceedings. Ekaterinburg : Uralskiy gosudarstvennyi gornyi universitet, 2016. pp. 67–72.
4. Zubov V. P., Smychnik A. D. The concept of reducing the risks of potash mines flooding caused by groundwater inrush into excavations. Journal of Mining Institute. 2015. Vol. 215. pp. 29–37.
5. Prugger F. F., Prugger A. F. Water problems in Saskatchewan potash mining—What can be learned from them? CIM Bulletin. 1991. Vol. 84, No. 945. pp. 58–66.
6. Danileva N. A., Danilev S. M. Bolshakova N. V. Allocation of a deep-lying brine aquifer in the rocks of a chemogenic section based on the data of geophysical well logging and 2D seismic exploration. Journal of Mining Institute. 2021. Vol. 250. pp. 501–511.
7. Baryakh A. A., Gubanova E. A. On flood protection measures for potash mines. Journal of Mining Institute. 2019. Vol. 240. pp. 613–620.
8. Kovalski E. R., Gromtsev K. V., Petrov D. N. Modeling deformation of rib pillars during backfill. GIAB. 2020. No. 9 . pp. 87–101.
9. Belyakov N. A., Belikov A. A. Prediction of the integrity of the water-protective stratum at the Verkhnekamskoye potash ore deposit. GIAB. 2022. No. 6-2. pp. 33–46.
10. Shiman M. I. Avoiding of flooding of potassium mines. Moscow : Nedra, 1992. 160 p.
11. Baryakh A. A., Krasnoshteyn A. E., Sanfirov I. A. Geotechnical accidents : Flooding of Berezniki Potash Mine 1. Vestnik Permskogo nauchnogo tsentra UrO RAN. 2009. No. 2. pp. 40–49.
12. Rauche H. Die Kaliindustrie im 21. Jahrhundert. Berlin : Springer Vieweg, 2015. 580 p.
13. Laptev B. V. Accidents at Upper Kama potash–magnesium salt deposit. Bezopasnost truda v promyshlennosti. 2009. No. 8. pp. 28–31.

14. Andreichuk V., Eraso A., Domínguez M. C. A large sinkhole in the Verchnekamsky potash basin in the Urals. Mine Water and the Environment. 2000. Vol. 19, Iss. 1. pp. 2–18.
15. Laptev B. V. Historiography of accidents in salt rock mining. Bezopasnost truda v promyshlennosti. 2011. No. 12. pp. 41–46.
16. Pachgin V. V. Justification of intense flat potash–magnesium seam mining under aquifers. Topical Issues of Subsoil Usage : Proceedings of International Forum–Contest of Young Scientists. Saint-Petersburg, 2015. Vol. 1. pp. 82–83.
17. Kvitkin S. Yu., Trofimov V. I., Kovalskaya V. V. Environmental efficiency and legal possibility of mineralized water dispose in the suprasalt sequence of the Verkhnekamskoe deposit. Journal of Mining Institute. 2017. Vol. 228. pp. 731–737.
18. Baryakh A. A., Andreiko S. S., Fedoseev A. K. Gas-dynamic roof fall during the potash deposits development. Journal of Mining Institute. 2020. Vol. 246. pp. 601–609.
19. Shemet S. F., Shutin S. G. Protection of potassium mines from brine inflows. Gornyi Zhurnal. 2014. No. 2. pp. 36–40.
20. Kuranov A. D., Bagautdinov I. I., Kotikov D. A., Zuev B. Yu. Integrated approach to safety pillar stability in slice mining in the Yakovlevo deposit. Gornyi Zhurnal. 2020. No. 1. pp. 115–119. DOI: 10.17580/gzh.2020.01.23
21. Bohnsack D., Potten M., Freitag S., Einsiedl F., Zosseder K. Stress sensitivi ty of porosity and permeability under varying hydrostatic stress conditions for different carbonate rock types of the geothermal Malm reservoir in Southern Germany. Geothermal Energy. 2021. Vol. 9. 15. DOI: 10.1186/s40517-021-00197-w
22. Petrakov D. G., Penkov G. M., Zolotukhin A. B. Experimental study on the effect of rock pressure on sandstone permeability. Journal of Mining Institute. 2022. Vol. 254. pp. 244–251.
23. Farid A. T., Rizwan M. Prediction of in situ Permeability for Limestone Rock Using Rock Quality Designation Index. International Journal of Geotechnical and Geological Engineering. 2017. Vol. 11, No. 10. pp. 948–951.
24. Ting Zhao, Yabin He, Li Song, Xiao Li, Xiaojuan Chen. Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone. ACS Omega. 2022. Vol. 7, Iss. 2. pp. 2147−2159.
25. Shabarov A. N., Kuranov A. D., Kiselev V. A. Assessing the zones of tectonic fault influence on dynamic rock pressure manifestation at Khibiny deposits of apatite–nepheline ores. Eurasian Mining. 2021. No. 2. pp. 3–7. DOI: 10.17580/em.2021.02.01
26. Shabarov A., Kuranov A., Popov A., Tsirel S. Geodynamic risks of mining in highly stressed rock mass. Problems in Geomechanics of Highly Compressed Rock and Rock Masses : Proceedings of the 1st International Scientific Conference. 2019. E3S Web of Conferences. 2019. Vol. 129. 01011. DOI: 10.1051/e3sconf/201912901011
27. Lamur A., Kendrick J. E., Eggertsson G. H., Wall R. J., Ashworth J. D. et al. The permeability of fractured rocks in pressurised volcanic and geothermal systems. Scientific Reports. 2017. Vol. 7. 6173. DOI: 10.1038/s41598-017-05460-4
28. Kozhevnikov E. V., Turbakov M. S., Riabokon E. P., Poplygin V. V. Effect of Effective Pressure on the Permeability of Rocks Based on Well Testing Results. Energies. 2021. Vol. 14, Iss. 8. 2306. DOI: 10.3390/en14082306
29. Mokhov A. V. Transformation of rock permeability at the underground mining areas of hard coal deposits (geomechanical aspects). Nauka Yuga Rossii. 2018. Vol. 14, No. 2. pp. 42–54.
30. Meye S. M., Zhenzhong Shen. Research on the Permeability Characteristics of Granite with Different Weathering Degrees before and after the Influence of Mining Method Construction. Engineering. 2020. Vol. 12, No. 6. pp. 382–400.
31. Fengda Zhang. Research on rock perm eability and failure characteristics under different loading and unloading paths. Acta Geophysica. 2022. Vol. 70, Is s. 3. pp. 1363–1371.
32. Rogov E. A. Study of the well near-bottomhole zone permeability during treatment by process fluids. Journal of Mining Institute. 2020. Vol. 242. pp. 169–173.
33. Grachev S. I., Korotenko V. A., Kushakova N. P. Study on influence of two-phase filtration transformation on formation of zones of undeveloped oil reserves. Journal of Mining Institute. 2020. Vol. 241. pp. 68–82.
34. Shestakov V. M. Hydrogeomechanics : Tutorial. Moscow : Izdatelstvo MGU, 1998. 72 p.
35. GOST 23278–2014. Soils. Field met hods for determining permeability. Moscow : Standartinform, 2015. 35 p.
36. Thiem G. Hydrologische Methoden. Leipzig, 1906.
37. Moye D. G. Diamond Drilling for Fou ndation Exploration. Civil Engineering Transactions. 1967. Vol. 9, No. 1. pp. 95–100.